Experimental model for heart failure in rats - Induction and diagnosis

Background: Clinical heart failure is generally preceded by hypertrophy. Many animal models (e.g. toxic heart failure models) do not consider this hypertrophy. We set out to develop a heart failure model in rats by inducing pressure-overload hypertrophy. Methods: We induced coarctation of the aortic arch with a tantalum clip (0.35 mm internal diameter) In 3-week-old rats (n= 17). Starting at seven weeks postoperatively, we measured ejection fraction (EF), fractional shortening (FS), end-systolic (LVESD) and end-diastolic (LVEDD) left ventricular dimensions by echocardiography each week. Heart, lung, and liver specimens were analyzed histopathologically at least eleven weeks after the operation. Results: Contractile function was significantly decreased in hearts from animals with aortic banding (EF: 45±5% vs. 73±5%, p<0.01; FS: 20±3% vs. 35±5%, p < 0.01). At the same time, left ventricles were dilated (LVEDD: 9.1±0.6mm vs. 7.4±0.5mm; LVESD: 7.3±0.6mm vs. 4.8± 0.4 mm, p < 0.01). These observations were associated with clinical and histopathological changes characteristic for chronic left heart failure. Conclusion: Placing a tantalum clip around the aortic arch in 3-week-old rats consistently induces left ventricular decrease in contractile function and dilatation after eleven weeks.